批量旋转混料机的研制及应用

介绍了批量旋转混料机的结构、性能与工作原理,以及正立方体混合室的翻转、推拉作用,使室内多组分聚合物在非熔融状态下的扩散,更换位置,以达到各组分混合物趋于均匀,即分布混合的目的。     

新型甲醇油气混合器的研究

随着对汽车节能和环保的要求日益提高,发展汽车代用燃料已经成为必然.甲醇是一种比较理想的代用燃料,为了实现甲醇裂解气在发动机进气道内充分混合,设计了不同结构的混合器.利用计算流体力学软件fluent,对混合器内流场进行模拟计算;最终结果表明能够更好地满足裂解气和空气的混合要求.     

某天然气发动机的文丘里管混合器结构参数设计

本文分别建立了天然气发动机所需燃气、空气流量的数学模型,以及文丘里管混合器结构参数的数学模型.在Matlab/Simulink仿真平台上进行了建模和仿真,获得了设计工况下文丘里管混合器的结构参数,并在发动机运行范围内满足过量空气系数稳定在1.7左右的设计要求.     

Extrusion-Spheronization of Blends of Carbopol 934 and Microcrystalline Cellulose

We evaluated the effects of several process variables on the pharmaceutical and drug release properties of extrusion-spheronization pellets of blends of Carbopol 934 and microcrystalline cellulose (MCC) containing a high proportion of Carbopol. The model drug was theophylline. Rheological monitoring during mixing was by mixer torque rheometry. Carbopol:MCC blends wetted with a CaCl₂ solution showed different rheological behavior compared to blends with a high proportion of MCC wetted with water only. In contrast to previous suggestions, the optimal wetting point for extrusion did not coincide with the point of peak torque, but occurred just beyond this point, at much lower torque. The influence of process variables on blend properties was investigated with a three-variable factorial design (Carbopol:MCC ratio, wetting liquid proportion, CaCl₂ :Carbopol ratio), and the influence of process variables on pellet properties with a four-variable design (the variables listed plus extrusion screen hole diameter). Blend torque values were strongly influenced by CaCl₂ proportion, while mean pellet diameter was influenced by Carbopol:MCC ratio. Mean pellet diameter also differed depending on whether the pellets contained theophylline. The observed among-formulation differences in theophylline release kinetics were largely explained by differences in pellet size and theophylline hydration state. Compaction of pellets to form tablets markedly modified the drug release profile, making it biphasic.     

丁苯橡胶凝聚釜搅拌器的优化改进

针对丁苯橡胶装置100 m3凝聚釜在运行中存在的搅拌效果不理想、釜内液面容易积胶、搅拌轴摆动大、中间轴承易磨损、调节拉杆易断裂等不足之处,提出了搅拌器改造方案。搅拌器采用CBY桨叶,取消中间轴承和调节拉杆,增大搅拌轴直径。这次改造满足了生产需要,改善了搅拌器搅拌效果,解决了搅拌器故障,延长了凝聚釜使用周期。     

FA022-6型多仓混棉机的可编程控制

为解决FA022-6型多仓混棉机电气控制系统可靠性差、运行过程中易堵车的问题,采用西门子公司S7-200系统的CPU222小型可编程控制器对原电气控制系统进行了技术改造,设计了自动换仓程序、防轧车程序.改造后,实现了自动换仓、故障报警等功能,棉仓梯度明显,混棉效果好.     

开环载波抑制设计方法研究

分析了射频发射机中影响载波抑制(CSR)特性的因素,提出相应的解决方法.为验证该设计方法,设计了一款含锁相环频率合成器的射频发射机,并进行流片.实验结果表明,在不进行任何修调和校准的情况下,载波抑制比常温可达到42 dBc,在-40℃～85℃温度范围内达到40～50 dBc,验证了该方法理论分析的正确性以及实现方法的可行性和实用性.     

Effect of amylose content on estimated kinetic parameters for a starch viscosity model

The apparent viscosity profile of starches during gelatinization varies with different amylose content. This study focused on the influence of amylose content on the kinetic parameters of a starch viscosity model for corn starches. The five parameters were: gelatinization rate constant (k_g), gelatinization activation energy (E_g), relative increase in apparent viscosity during gelatinization (A^α), relative decrease in apparent viscosity during shearing (B), and viscous activation energy (E_v). The parameters were estimated at different amylose content using both ordinary least squares nonlinear regression and the sequential method. The mixer viscometry approach was used to measure apparent viscosity. The first part of this paper presents parameter estimation results for waxy corn starch. The model was validated by using the parameters to predict viscosity for the same starch in a different measuring system, i.e., the RVA. The second part of this paper presents the estimated parameters for corn starch blends at different amylose content. The following parameters were significantly affected by amylose content: k_g and E_g both decreased with amylose content by an power-law relationship. Activation energy of gelatinization ranged from 121 to 1169 kJ/mol. The other parameters A^α, B, and E_v were not significantly influenced by amylose content. In summary, the gelatinization parameters k_g and E_g dramatically decreased as amylose increased from 3% to 35% (waxy corn starch blends).     

Comparative Assessment of Bromate Control Options

Various bromate control options were assessed through an intensive pilot testing program, performed with a four-cell bubble contactor, and focused on intermediate ozonation of conventionally-treated sand-filtered water. Both acid addition and ammonia addition independently provided good bromate reduction, with their combinational addition providing no further reduction. On a CT basis, the use of a static mixer did not increase bromate formation, while staged ozonation enhanced bromate formation over single stage application.     

8种搅拌器搅拌特性的实验研究

在375mm的搅拌釜内,对8种搅拌器进行实验,考察了搅拌器桨型、转速及密度等操作因素对各种搅拌器的搅拌功率和搅拌时间的影响。研究表明,综合考虑单位体积的搅拌功率和混合时间,所提出的二层组合桨的混合效率数Ce最小,混合效率最高。